xxvi Journal of Comparative Neurology. 



geus is the r. pre-trematicus IX; and that his first branchial of the vagus is 

 the r. UnguaHs or post-trematicus of the glossopharyngeus. The fact 

 that Professor Kingsley's second and third branchial nerves in Am- 

 phiuma agree with the first and second branchial trunks of the vagus, 

 as I have described them, in Amblystoma (1. c.) in their origin and 

 distribution is additional evidence to support my conclusion. 



The r. supratemporalis is recognized as a branch of the glosso- 

 pharyngeal trunk, and with its description the author gives an in- 

 structive comparative discussion. The hypoglossal is formed from the 

 first two spinal nerves, each of which has a dorsal root and ganglion. 



G. E. COGHILL. 



Regeneration of Peripheral Neryes.' 



Fleming summarizes the literature on nerve regeneration in the 

 brief statement that there are two theories as to the manner in which 

 peripheral nerves regenerate, (i) The old or central theory, which is 

 that regeneration occurs only from the central end of a divided nerve 

 as a result of the downward growth of central nerve fibers or the axis 

 cylinders of such fibers, in which latter case a new neurilemma is de- 

 veloped from neurilemma nuclei which proliferate during the degener- 

 ation of the peripheral segment. This theory Fleming regards as in- 

 validated by the fact that in a number of cases of secondary nerve- 

 suture, sensation returned, in part at least, in the realm of the sutured 

 nerve in 24 hours, more generally in two to three days; also by a num- 

 ber of more recently recorded observations. (2) The new or peri- 

 pheral theory, according to which complete degeneration takes place 

 in the peripheral portion of a divided nerve within a period of three to 

 four weeks after section. Within the old neurilemma sheaths, there 

 are developed from the neurilemma nuclei a varying number of cells 

 with large oval nuclei and granular protoplasm, "which, after becom- 

 ing arranged in more or less regular columns, begin to act as neuro- 

 blasts." A wavy axis-cyhnder develops close to the nucleus of a 

 young neuroblast, grows and soon becomes separated from the young 

 nucleus by a distinct gap. This young axis- cylinder later becomes in- 

 vested with a delicate myelin sheath which is either secreted or other- 

 wise developed; the neuroblasts eventually forming the primitive sheath 

 just as in a fully developed nerve fiber. "The new axis-cylinders, while 

 they are joined together to form more or less continuous chains, do not 



^The Peripheral Theory of Nerve Regeneration with Special Reference to 

 Peripheral Neuritis. By R. A. Fleming, M. A., M. D., F. R. C. P., Ed. Tht 

 Scottish Midtcal and Sur^(al /gi^rnal. Vol. XI., No. 3, September, I902. 



